@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700;800&family=Outfit:wght@400;500;600;700;800&display=swap');
:root{font-family:Outfit,'DM Sans',system-ui,sans-serif;color:#123347;background:#e9f7f6;font-size:17px}*{box-sizing:border-box}body{margin:0;background:radial-gradient(ellipse at top,#def9f4,#f3faf9 65%)}button,select{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.5}a{color:inherit}button:focus-visible,a:focus-visible,select:focus-visible{outline:3px solid #e2a439;outline-offset:3px}[hidden]{display:none!important}.quiz-shell{max-width:1360px;margin:auto}.quiz-header{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:20px clamp(20px,4vw,55px);background:#fff;border-bottom:1px solid #d8eeeb}.wordmark{text-decoration:none;font-size:27px;font-weight:800;color:#0d555a;white-space:nowrap}.wordmark>span:not(.brand-leaf){color:#143247}.wordmark small{font-size:10px;letter-spacing:.2em;margin-left:4px}.brand-leaf{color:#29b96e}.lesson-label{font-size:13px;font-weight:800;letter-spacing:.13em;color:#386473}.lesson-label 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auto;padding:22px;width:175px;height:175px;border-radius:100%;border:8px solid #91e7b9;background:#0c686b;display:flex;flex-direction:column;justify-content:center}.score-circle strong{font-size:43px}.score-circle small{font-size:13px}.finish-actions{display:flex;justify-content:center;gap:12px;flex-wrap:wrap}.finish h2{margin-top:30px}.finish h2 small{font-size:16px;color:#539589}.review{display:grid;gap:12px}.review-item{padding:19px;background:white;border-radius:18px;border:1px solid #cae7e3}.review-item h3{margin:0 0 8px}.review-item p{line-height:1.5;margin:8px 0}.review-item small{color:#518077}footer{text-align:center;padding:30px;color:#648387;font-size:13px}footer span{color:#0e987c;margin:0 10px}@media(max-width:800px){.header-pill,.lesson-label{display:none}.hero{min-height:350px;background-image:linear-gradient(90deg,#052c3de8,#06354883),url('/chemical-quiz-scene.webp');background-position:57% center}.journey{grid-template-columns:1fr}.play-grid{grid-template-columns:1fr}.side-card{display:none}.options{grid-template-columns:1fr}.question-actions{align-items:stretch;flex-direction:column-reverse}.start-controls,.start-controls label,.start-controls select,.start-controls .primary{width:100%}.quiz-header{padding:15px 20px}.wordmark{font-size:24px}}@media(prefers-reduced-motion:reduce){*,*::before,*::after{transition:none!important;animation:none!important}}

.hero-cta{display:inline-block;margin-top:22px;background:#a5eabe;color:#063e46;border-radius:13px;padding:13px 20px;text-decoration:none;font-weight:800;box-shadow:0 4px 0 #3eaa86}.hero-cta:hover{background:#c2f2d4}.hero-cta:focus-visible{outline:3px solid #fff;outline-offset:4px}
/* Reaction Journey: the approved bright BioGenius quiz treatment. */
:root{color:#173c4e;background:#ebfbfa}
body{background:radial-gradient(circle at 6% 21%,#d9fff3 0,transparent 25%),radial-gradient(circle at 94% 38%,#cdebf9 0,transparent 29%),linear-gradient(180deg,#ecfcf8,#f5fcfb)}
.quiz-shell{max-width:1540px}
.quiz-header{position:sticky;z-index:5;top:0;box-shadow:0 7px 23px #07576313;border-bottom:2px solid #cbebe5;background:#fffffff2;backdrop-filter:blur(12px)}
.header-controls{display:flex;align-items:center;gap:10px}
.music-toggle{white-space:nowrap;border-radius:999px;border:1px solid #89cfc7;background:#e9fbf6;color:#12695e;padding:9px 15px;font-weight:800;box-shadow:0 3px 0 #b5e4d7}
.music-toggle[aria-pressed=true]{background:#099883;color:white;border-color:#099883;box-shadow:0 3px 0 #087666}
.music-volume{display:flex;align-items:center;gap:5px;color:#387b79;font-size:12px;font-weight:700}.music-volume input{width:80px;accent-color:#00a897}
.intro,.play,.finish{padding:clamp(15px,2.3vw,32px)}
.hero{background-color:#f0fffb;background-image:linear-gradient(90deg,#f2fffcfc,#e3fbf3ce 53%,#c7eff169),url('/chemical-quiz-scene.webp');box-shadow:0 17px 36px #3283791c;border:2px solid white;min-height:310px}
.hero-content{color:#143d4e}.hero h1 em{color:#008f7a}.hero-content>p:not(.overline){color:#315e6a}.hero-tags span{background:white;border-color:#b8e5d9;color:#26766f}.hero-cta{background:#009c86;color:white;box-shadow:0 4px 0 #08786d}.overline{color:#087e76}
.play-heading{background:linear-gradient(110deg,#fff,#e2faf6);padding:20px 25px;border-radius:23px;border:1px solid #d4eee9;box-shadow:0 8px 22px #157e7510}.play-heading h1{margin-bottom:0;letter-spacing:-.02em}.countdown{background:#d7f9ee;border:1px solid #a5e9d8}
.chapter-chain{background:white;border:1px solid #c7e9e3;border-radius:21px;margin:15px 0 0;padding:16px 18px;box-shadow:0 8px 22px #158a8012;display:flex;justify-content:space-between;gap:9px;overflow-x:auto;scrollbar-width:thin}
.chain-group{flex:1;min-width:244px}.chain-group+ .chain-group{border-left:1px solid #d6eeea;padding-left:13px}.chain-title{font-size:11px;letter-spacing:.09em;font-weight:800;color:#44777b;text-transform:uppercase;margin-bottom:10px;white-space:nowrap}.chain-circles{display:flex;align-items:center;justify-content:space-around;gap:0}.chain-item{display:contents}.chain-link{height:3px;min-width:7px;flex:1;background:#c9e5df}.chain-link.done{background:#50c797}.chain-link.missed{background:#ec9798}.chain-dot{display:grid;place-items:center;flex:none;width:33px;height:33px;border:2px solid #bbd8da;border-radius:50%;background:#fff;color:#55828a;font-size:13px;font-weight:800;padding:0;box-shadow:none}.chain-dot:disabled{opacity:1;cursor:default}.chain-dot.current{border-color:#06a7b0;background:#07b2b7;color:#fff;box-shadow:0 0 0 4px #d3f6f4}.chain-dot.correct{background:#18b779;color:#fff;border-color:#12a96e}.chain-dot.incorrect{background:#f27278;color:white;border-color:#df5a64}.chain-dot.answered{cursor:pointer}.chain-dot.answered:hover{transform:scale(1.1)}.chain-help{font-size:12px;font-weight:650;color:#4b8584;margin:8px 6px 14px}.progress-meta{margin-top:2px}progress{height:7px;margin-bottom:19px}
.play-grid{grid-template-columns:minmax(160px,250px) minmax(430px,1fr) minmax(170px,240px);gap:15px;align-items:start}.scientist-rail,.side-card{min-width:0;position:sticky;top:98px}.scientist-rail{border-radius:25px;border:1px solid #c3e7df;background:linear-gradient(155deg,#f7fffc,#d7f6eb);box-shadow:0 12px 29px #1d7b7217;overflow:hidden;padding:10px 9px 16px;text-align:center}.mascot-frame{height:330px;display:flex;align-items:flex-end;justify-content:center;overflow:hidden}.mascot-frame img{display:block;max-width:100%;height:100%;object-fit:contain;object-position:center bottom;filter:drop-shadow(0 10px 9px #0b655626)}.mascot-note{font-weight:800;color:#08756c;font-size:19px}.mascot-note span{display:block;font-size:15px;margin-top:5px}.side-card{background:linear-gradient(160deg,#e4faf8,#f4fffb);color:#145268;padding:13px;border:1px solid #c8e8e3;box-shadow:0 12px 27px #0a71630e}.side-visual{height:225px;border-radius:17px;background:#bcecf0 url('/biology-objects.png') center 42%/cover no-repeat;border:1px solid #a7dbda}.side-card .overline{color:#077c71;margin-top:14px}.side-card li{border-color:#a9d9d1;padding:8px 9px;margin-bottom:5px}.side-card li.current{border-color:#0ab995;background:#d8f6ed}.side-card li.done{border-color:#1bb77c}.side-card li small,.side-card>p:not(.overline){color:#497983}.side-caption{background:#d4f3ed;color:#176463;padding:11px;font-size:13px}
.question-card{padding:clamp(22px,2.3vw,36px);border:1px solid #cceae6;box-shadow:0 14px 35px #1a756b15}.question-type{letter-spacing:.1em;color:#058d80}.question-card h2{color:#183c4c;font-size:clamp(24px,2.5vw,34px);line-height:1.22}.diagram{background:linear-gradient(120deg,#f0fbf8,#e8f7f8);border:1px solid #c3e9e4}.options{gap:12px}.option{min-height:82px;border-radius:15px;font-size:18px;font-weight:750}.option:nth-child(4n + 1){background:#ecf8ff;border-color:#b6def1}.option:nth-child(4n + 2){background:#ebf9f0;border-color:#bce6ca}.option:nth-child(4n + 3){background:#fff6e8;border-color:#f2daba}.option:nth-child(4n){background:#f4efff;border-color:#d7c9f2}.option.selected{background:#d4f6f1!important;border-color:#078f8e!important;box-shadow:0 0 0 2px #078f8e33}.option.correct{background:#e0fae7!important;border-color:#20ad73!important}.option.wrong{background:#ffebec!important;border-color:#dd6471!important}.option .letter{border-radius:50%;width:36px;height:36px;color:#136b70}.primary,.sign-in{background:linear-gradient(135deg,#0cbc9b,#038475);box-shadow:0 4px 0 #047264}.primary:not(:disabled):hover{background:#048270}.feedback{background:#e4faef;border-color:#9bd8be}.feedback.miss{background:#fff6f1}.feedback .overline{color:#07846a}.feedback #feedbackArabic{border-top:1px solid #b9e9d4;padding-top:12px;font-weight:600;color:#296768}
.finish-hero{background:linear-gradient(115deg,#eafff8f1,#ddf9f2dc),url('/chemical-quiz-scene.webp') center/cover;border:1px solid #bde6db;color:#154b54}.finish-hero .overline{color:#06796d}.score-circle{background:#078e80;color:white}.review-item{box-shadow:0 5px 14px #0b827414}
.past-dialog{width:min(92vw,650px);border:1px solid #a8dbcd;border-radius:23px;padding:30px;background:#f9fffd;color:#173c4e;box-shadow:0 28px 70px #143c4e63}.past-dialog::backdrop{background:#0a364583;backdrop-filter:blur(3px)}.past-dialog h2{line-height:1.25}.past-dialog p{line-height:1.5}.past-dialog #pastArabic{font-size:18px;color:#126d64}.dialog-close{float:right;border:0;border-radius:50%;background:#e3f5f1;color:#13545c;width:37px;height:37px;font-weight:800}.past-dialog small{color:#578079}
@media(max-width:1150px){.play-grid{grid-template-columns:150px minmax(0,1fr)}.side-card{display:none}.mascot-frame{height:260px}.mascot-note{font-size:15px}}
@media(max-width:750px){.quiz-header{position:relative;flex-wrap:wrap;gap:6px}.wordmark{font-size:23px}.header-pill{display:none}.header-controls{margin-left:auto}.play-heading{padding:14px}.play-heading h1{font-size:24px}.play-grid{grid-template-columns:1fr;gap:9px}.scientist-rail{position:static;display:flex;align-items:center;padding:5px 13px;height:82px;order:0}.mascot-frame{height:75px;width:77px;flex:none}.mascot-note{font-size:14px;text-align:left}.mascot-note span{font-size:12px}.question-card{order:1}.chapter-chain{padding:12px}.chain-group{min-width:235px}.options{grid-template-columns:1fr}.option{min-height:65px}.question-actions{flex-direction:column-reverse}.question-actions>*{width:100%}.music-volume input{width:58px}.play-heading .countdown{padding:8px;font-size:12px}}
@media(max-width:390px){.music-volume{display:none}.chain-help{font-size:11px}}
/* Final polish: sharper answer states without changing the journey layout. */
.question-card{min-width:0;border-color:#b8ded9}.question-card h2{color:#12374a}
.option{position:relative;min-width:0;border-width:2px;box-shadow:0 2px 0 #0c57600a;line-height:1.35;overflow-wrap:anywhere;transition:background .18s ease,border-color .18s ease,box-shadow .18s ease,transform .18s ease}
.option:hover:not(:disabled){transform:translateY(-2px);border-color:#087f83;box-shadow:0 5px 13px #146d7024}
.option.selected{box-shadow:0 0 0 3px #078f8e2a}.option.correct,.option.wrong{opacity:1!important;box-shadow:0 0 0 1px #ffffff inset}
.option.correct{background:#d7f6e4!important;border-color:#11865f!important;color:#0c563f}.option.wrong{background:#ffe1e3!important;border-color:#c8364e!important;color:#8c2035}
.option.correct .letter{color:#08694c}.option.wrong .letter{color:#a1263d}
.result-mark{display:grid;place-items:center;flex:none;margin-left:auto;width:30px;height:30px;border-radius:50%;font-weight:900;font-size:19px;background:#138a60;color:white}
.option.wrong .result-mark{background:#c8364e}
.diagram .equation{color:#084d63;font-family:Outfit,Arial,sans-serif;font-size:clamp(23px,3vw,35px);font-weight:800;letter-spacing:.015em;line-height:1.35}
.diagram{max-width:100%;overflow-x:auto}.diagram small{font-size:14px;color:#3d6870}
.feedback{border-width:2px;color:#194653}.feedback h3{color:#0b6454}.feedback.miss h3{color:#854b34}.feedback #feedbackEnglish{font-weight:600}
.scientist-rail.cheer .mascot-frame img{animation:mascot-cheer .62s ease-out}.scientist-rail.encourage .mascot-frame img{animation:mascot-encourage .48s ease-out}
@keyframes mascot-cheer{50%{transform:translateY(-8px) rotate(-2deg)}}@keyframes mascot-encourage{50%{transform:rotate(2deg)}}
@media(max-width:750px){.option{min-height:67px;padding:13px 15px}.result-mark{width:28px;height:28px}.question-card h2{overflow-wrap:anywhere}}
/* A separate, opt-in sound switch keeps applause independent of the music. */
.feedback-sound-toggle{background:#f1f8ff;color:#15536b;border-color:#a7d0e0;box-shadow:0 3px 0 #ccdfed}
.feedback-sound-toggle[aria-pressed=true]{background:#087e83;color:white;border-color:#087e83;box-shadow:0 3px 0 #065b65}
@media(max-width:1020px){.quiz-header .lesson-label{display:none}}
@media(max-width:750px){.header-controls{flex-wrap:wrap;justify-content:flex-end}.feedback-sound-toggle,.music-toggle{font-size:12px;padding:8px 10px}}
/* The same scientist becomes visibly expressive, without covering the quiz. */
.mascot-frame{position:relative}.mascot-frame img{animation:scientist-idle 12s ease-in-out infinite;transform-origin:50% 86%}
.mascot-speech{position:relative;z-index:1;margin:0 7px 9px;padding:9px 10px;border:2px solid #73dabb;border-radius:15px;background:#fff;color:#086759;font-size:18px;line-height:1.15;font-weight:800;box-shadow:0 5px 12px #147e6e1c}
.mascot-speech::before{content:"";position:absolute;top:-8px;left:45%;width:12px;height:12px;transform:rotate(45deg);background:#fff;border-left:2px solid #73dabb;border-top:2px solid #73dabb}
.scientist-rail.cheer .mascot-frame img{animation:scientist-celebrate 1.2s cubic-bezier(.2,.8,.2,1) both}
.scientist-rail.encourage .mascot-frame img{animation:scientist-encourage .95s ease-in-out both}
.mascot-sparkle{pointer-events:none;position:absolute;color:#f2af39;opacity:0;font-size:23px;text-shadow:0 2px #ffffff}.sparkle-one{top:18%;left:8%}.sparkle-two{top:34%;right:7%}
.scientist-rail.cheer .mascot-sparkle{animation:scientist-sparkle 1.2s ease-out}.scientist-rail.cheer .sparkle-two{animation-delay:.14s}
@keyframes scientist-idle{0%,12%,35%,70%,100%{transform:translateY(0) rotate(0)}17%{transform:translateY(-4px) rotate(-1deg)}22%{transform:translateY(-2px) rotate(.6deg)}75%{transform:rotate(1deg)}}
@keyframes scientist-celebrate{0%{transform:translateY(0) rotate(0) scale(1)}28%{transform:translateY(-17px) rotate(-5deg) scale(1.04)}52%{transform:translateY(-3px) rotate(4deg) scale(1.025)}72%{transform:translateY(-11px) rotate(-3deg) scale(1.035)}100%{transform:translateY(0) rotate(0) scale(1)}}
@keyframes scientist-encourage{0%,100%{transform:translateY(0) rotate(0)}33%{transform:translateY(-5px) rotate(3deg)}65%{transform:translateY(-2px) rotate(-3deg)}}
@keyframes scientist-sparkle{0%,100%{opacity:0;transform:translateY(0) scale(.6)}35%{opacity:1;transform:translateY(-15px) scale(1.2)}70%{opacity:.8;transform:translateY(-23px) scale(.9)}}
@media(max-width:750px){.mascot-speech{margin:0 4px;font-size:14px;padding:8px}.scientist-rail.cheer .mascot-note,.scientist-rail.encourage .mascot-note{display:none}}
@media(prefers-reduced-motion:reduce){.mascot-frame img,.scientist-rail.cheer .mascot-frame img,.scientist-rail.encourage .mascot-frame img,.scientist-rail.cheer .mascot-sparkle{animation:none!important;transform:none!important}}
/* Compact question navigation sticks while the page header scrolls away. */
.quiz-header{position:relative;top:auto;z-index:1;backdrop-filter:none}
.chapter-chain{position:sticky;top:0;z-index:12;margin:10px 0 0;padding:9px 14px;border-radius:0 0 16px 16px;border:1px solid #8ecfc9;background:#fffffff8;box-shadow:0 7px 17px #123c4d26;backdrop-filter:blur(8px)}
.chain-title{margin-bottom:6px;font-size:10px}.chain-dot{width:30px;height:30px}.chain-help{margin:7px 6px 12px}
.question-card h2{font-weight:600;color:#0c3045;line-height:1.34;font-size:clamp(23px,2.45vw,32px);scroll-margin-top:94px}
.question-card h2.question-long{font-size:clamp(21px,2.15vw,28px);line-height:1.39}
.options .option{background:#fff;border-color:#b6cfd8;box-shadow:0 2px 5px #0d46520e}
.options .option:nth-child(even){background:#f5faff;border-color:#b6cfd8}
.options .option:hover:not(:disabled){transform:translateY(-1px);border-color:#167e94;box-shadow:0 6px 15px #123c4d1c}
.options .option.selected{background:#e6f0fa!important;border-color:#216b93!important;color:#103c59;box-shadow:0 0 0 3px #216b9327}
.options .option.selected .letter{color:#16567c}
.options .option.correct{background:#d7f6e4!important;border-color:#11865f!important;color:#0c563f}
.options .option.wrong{background:#ffe1e3!important;border-color:#c8364e!important;color:#8c2035}
.options .result-mark{visibility:hidden}.options .result-mark.revealed{visibility:visible}
.question-actions{min-height:58px}.hint-button{font-size:14px;color:#315e6b;border:1px solid #c7e4e2;background:#f6fbfa;border-radius:11px;padding:9px 13px}.hint-button:hover:not(:disabled){background:#e9f7f4}
#submit:disabled{background:#d2e4e4;color:#577579;box-shadow:none;opacity:1}#submit:not(:disabled){background:linear-gradient(135deg,#058a88,#057269)}
@media(max-width:1150px){.play-grid .side-card{display:block;position:static;grid-column:1/-1}.play-grid .side-visual{display:none}.play-grid .side-card ol{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:7px;margin-bottom:5px}.play-grid .side-caption{font-size:12px}}
@media(max-width:750px){.chapter-chain{top:0;padding:8px 11px}.chain-dot{width:30px;height:30px}.play-grid .side-card{order:2}.play-grid .side-card ol{grid-template-columns:1fr}.play-grid .side-card li{flex-direction:row;justify-content:space-between}.play-grid .side-card>p:not(.overline),.play-grid .side-caption{display:none}.question-card h2{font-size:clamp(22px,6vw,29px)}.question-card h2.question-long{font-size:clamp(20px,5.4vw,25px)}.options .option{font-size:16px}.question-actions{min-height:0}}